Mars is expanding its Maltesers brand into a chocolate bar format for the first time.

Available in two sizes - a countline and a sharing block - from the end of this month, Maltesers Teasers is the first product launched by Mars since it invested £6m in a new R&D facility last autumn.

The new chocolate bars are similar to the Maltesers sweets found in Mars’ Celebrations selection boxes, and contain tiny pieces of Malteser.

“What we’ve come up with is based on the Celebrations Maltesers, but we wanted to intensify the amount of chocolate while keeping the crunch,” said Mars Chocolate R&D director Geoff Bryant.

To achieve this, Mars has built a dedicated production line at its Slough site to make the tiny Maltesers pieces in the new bars.

“The new line has meant we are able to create smaller centres using exactly the right mould for the perfect bite,” added Bryant.

Mars said it was hoping the launch would reinvigorate the block category, which it claimed had seen limited innovation.

The launch will be supported by a £4m marketing campaign including a new ad airing in April and Mars said it would also be increasing its year-on-year spend on the core Maltesers brand.

Maltesers is the third-largest chocolate confectionery brand in the UK and is outperforming the overall chocolate confectionery market, with sales up 6.5% year-on-year to £152.6m in a category up 3.4% [Nielsen 52 w/e 13 October 2012]. The brand’s last big piece of NPD was the Malteaster Bunny novelty in 2009.

The launch of Teasers makes Maltesers the latest in a string of confectionery brands to have branched into bars. These include the Rolo bar launched by Nestlé a year ago, and the Creme Egg Twisted bar rolled out by Cadbury in 2008.